Dr Bywaters, who worked for the Department of Health before she retired, told The Star the election plans were at a very early stage - but said she would be prepared to stand against Mr Clegg.

“This bill is an affront to democracy. It wasn’t in the coalition agreement and I think a lot of people feel it is not what they voted for,” said the 64-year-old, whose Millhouses home is in Mr Clegg’s Sheffield Hallam constituency.

Dr Bywaters said campaigners had not yet discussed who would stand in the election, or which constituencies they would target, but said: “It is a possibility that I will stand.”

She added: “I think these reforms will lead to fragmentation of the health service, and the new Clinical Commissioning Groups may not be obliged to offer everything that is currently offered in the NHS.”

Ministers say the reforms will hand control over health budgets to GPs and reduce bureaucracy.

But Dr Bywaters said: “The skills of GPs are very great but they are not trained in commissioning.”

Dr Grunewald, who is based at the Royal Hallamshire Hospital, said he would not stand for parliament himself, but added: “People will vote for a candidate who would promote the reversal of the more dangerous aspects of this bill.

“The NHS is such a complex organisation that any small change will have unforeseen ramifications. It needs evolution, not revolution.”

Dr Evans said she had agreed to be part of the group planning the campaign.

She added: “This is a destructive bill that undermines the founding principles of the NHS. We need to protect the service for our patients.”